Hvac system for buildings

ABSTRACT

A ventilation system comprises a plurality of axial fan units, each having at least one axial fan having a rotational axis generally parallel to a downstream flow caused by the axial fan, and at least one grill positioned adjacent to the at least one axial fan in a downstream flow path of the axial fan unit, the at least one grill directing an air flow of the axial fan. At least a first series of the plurality of axial fan units is adapted to be positioned at a top of a plenum arrangement extending from a bottom front of a refrigerated enclosure, to a rear back of the refrigerated enclosure, said top being at a top of the rear back. At least a second series of the plurality of axial fan units is adapted to be positioned above an area to cool and oriented to project its downstream flow in a downward direction to direct its downstream flow to said area to cool. The first series of the plurality of axial fan units is oriented to project its downstream flow in an upward direction toward the second series of the plurality of axial fan units such that the first series is adapted to direct air from the plenum arrangement to the second series.

TECHNICAL FIELD

The present application relates to ventilation systems for buildings and refrigeration systems found in medium scale and large scale surfaces, such as those found in supermarkets for refrigerated counters and enclosures, in relation to HVAC needs (heating, ventilation and air conditioning).

BACKGROUND OF THE ART

Supermarkets of medium scale and large scale surfaces conventionally have many alleys equipped with rows of refrigerated counters and enclosures. The refrigerated counters and enclosures come in various forms, and are commonly found in open configuration. In the open configuration, there is no door to maintain the cold inside the counters. Islands, semi-vertical enclosures, multi-deck vertical enclosures may have an open configuration.

As a result of the open configuration, the ambient temperature in the vicinity of refrigerated counters may be uncomfortably low. For example, in the warmer months of a year, or in warmer climates, shoppers may be dressed lightly based on the outdoor temperature, and may consequently find unpleasant the shopping experience when walking through alleys of refrigerated enclosures. Supermarkets are thus equipped with HVAC systems to climate different sections of supermarkets. This may include generating heat for cooler sections of the supermarket in spite of the warm outdoor temperature, and operating an air-conditioning cycle to cool other sections of the supermarket. Such use may be inefficient in terms of energy costs, with the usual drawbacks also present: carbon footprint of energy consumption, global warming, etc.

SUMMARY

In one aspect, a ventilation system comprising: a plurality of axial fan units, each having at least one axial fan having a rotational axis generally parallel to a downstream flow caused by the axial fan, and at least one grill positioned adjacent to the at least one axial fan in a downstream flow path of the axial fan unit, the at least one grill directing an air flow of the axial fan; wherein at least a first series of the plurality of axial fan units is adapted to be positioned at a top of a plenum arrangement extending from a bottom front of a refrigerated enclosure, to a rear back of the refrigerated enclosure, said top being at a top of the rear back; wherein at least a second series of the plurality of axial fan units is adapted to be positioned above an area to cool and oriented to project its downstream flow in a downward direction to direct its downstream flow to said area to cool; and wherein the first series of the plurality of axial fan units is oriented to project its downstream flow in an upward direction toward the second series of the plurality of axial fan units such that the first series is adapted to direct air from the plenum arrangement to the second series.

In another aspect, a refrigeration controller system for operating a refrigeration, a ventilation system and a HVAC system comprising: a processing unit, and a non-transitory computer-readable memory communicatively coupled to the processing unit and comprising computer-readable program instructions executable by the processing unit for operating the refrigeration system to cool refrigerated enclosures; operating the ventilation system as described above to provide cold heat to a facility recuperated from said refrigerated enclosures; reclaiming heat from the refrigeration system; and operating the HVAC system with the heat reclaimed from the refrigeration system to provide heated air; wherein the refrigeration controller system operates when an outdoor temperature is greater than 20 C.

In another aspect, there is provided a heating, ventilating and air conditioning (HVAC) system, comprising: a central unit, comprising: a compressor operable to provide compressed refrigerant, a condenser at a refrigerant inlet fluidly connected to a refrigerant outlet of the compressor via a compressed refrigerant line to receive the compressed refrigerant from the compressor, and a first fan operatively connected to the condenser to move air through the condenser; a plurality of terminal units, each terminal unit of the plurality of terminal units comprising, in serial air flow communication: a cooling coil fluidly connected: at a refrigerant inlet thereof, to a refrigerant outlet of the condenser to receive refrigerant from the condenser, and at a refrigerant outlet thereof, to a refrigerant inlet of the compressor to supply evaporated refrigerant to the refrigerant inlet of the compressor; a heating coil fluidly connected: at a refrigerant inlet thereof, to the compressed refrigerant line at a first location that is fluidly between the refrigerant outlet of the compressor and the refrigerant inlet of the condenser, and at a refrigerant outlet thereof, to the compressed refrigerant line at a second location that is fluidly between the first location and the refrigerant inlet of the condenser; and a second fan operable to move air through the cooling coil and the heating coil.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a ventilation system for refrigerated enclosure in accordance with a first embodiment of the present disclosure;

FIG. 2A is a face view of an axial fan unit used in the ventilation system of FIG. 1;

FIG. 2B is a rear view of the axial fan unit used in the ventilation system of FIG. 1;

FIG. 3 is a perspective view of the enclosure-top axial fan unit used in the ventilation system of FIG. 1;

FIG. 4 is a schematic view of a ventilation system for refrigerated enclosure in accordance with a second embodiment of the present disclosure;

FIG. 5 is a schematic block diagram showing a relation between the ventilation systems of FIGS. 1 to 4, a refrigeration system and a HVAC system;

FIG. 6 is a schematic elevation view showing a building having an HVAC system interlinked with multiple refrigeration systems;

FIG. 7 is a schematic plan view showing a roof of the building of FIG. 6, with a central unit of the HVAC system disposed on the roof, and multiple terminal units of the HVAC system being disposed in spaces inside the building.

DETAILED DESCRIPTION

Referring to FIG. 1, a ventilation system in accordance with the present disclosure is generally shown at 10, relative to refrigerated enclosures A. The refrigerated enclosures A are illustrated as being of the multi-deck type, with open configuration. Other types of refrigerated enclosures could be equipped with the ventilation system 10, including semi-vertical, island, etc, in open configuration but could also be in a closed configuration. There may a single row of the refrigerated enclosures A instead of the two rows shown in FIG. 1. Moreover, although the end view of FIG. 1 shows only a pair of refrigerated enclosures A, there may be a plurality of side-by-side refrigerated enclosures A, for example all along alley B. The alley B is shown as the space by which consumers access the refrigerated enclosures A. In FIG. 1, the alley B is delimited by the two rows of refrigerated enclosures A, but could also be delimited by a single row of refrigerated enclosures A and shelves. Islands may also be in the alley B. For the purpose of explaining the ventilation system properly, an air space is generally shown at C. The air space C may be defined at the space or volume above the refrigerated enclosures A and alley B, and below the ceiling D.

The refrigerated enclosures A are typically add-on equipment. As such, there may be plenums E1 and E2 defined respectively at a bottom and at a back of the refrigerated enclosures A. The plenum E1 is between the bottom of the refrigerated enclosures A and the ground, whereas the plenum E2 is between the back of the refrigerated enclosure A and a wall or structure against which the refrigerated enclosures A have their back, such as another row of refrigerated enclosures A, a row of shelves, etc.

The ventilation system 10 has axial fan units 20 (FIGS. 2A and 2B) and 20′ (FIG. 3). The axial fan units 20 and 20′ each have one or more axial fans 21, such as rows of axial fans 21. In an embodiment, the axial fan units 20/20′ are electrically wired so as to be independently powered (e.g., off the 120V general supply), such that failure of one of the axial fan units 20/20′ does not cause a complete shutdown of the ventilation system 10. Hence, the ventilation system 10 has a redundancy for continuous operation. When the axial fan units 20 and 20′ have more than one axial fan 21, the axial fans 21 may be in a side-by-side relation, to describe the fact that the axial fans 21 are in a parallel arrangement relative to one another, as opposed to being serially arranged in a duct. More specifically, as shown in FIGS. 2A and 2B, each of the axial fan units 20 is of the type having a square or rectangular housing 22 for a refrigerant outlet 23 of any appropriate shape. In FIGS. 2A and 2B, there are a pair of axial fans 21 with a generally rectangular outlet 23 spanning over the two axial fans 21. In FIG. 3, the axial fan unit 20′ has a rectangular housing 22, though with a front face 22A being angled related to a rear face 22B. In other words, the front face 22A is in a plane that is angled relative to a plane of the rear face 22B by an angle θ, with angle θ being between 10 degrees and 45 degrees. Still in FIG. 3, there are a pair of circular outlets 23. The axial fan unit 20′ could also be equipped with a single axial fan 21 or a single outlet 23 spanning all axial fans 21, in any suitable shape.

The axial fan unit 20/20′ is said to be axial in that an axis of rotation of the fan(s) 21 is generally parallel to a flow direction out of the fan unit 20. The axis of rotation of the axial fan unit 20 would project out of the page for FIGS. 2A and 2B. The axes of rotation for the axial fan unit 20′ are generally shown at X. This orientation is advantageous in that the side-by-side arrangement of axial fan units 20 is relatively compact compared to squirrel cages. The axial fan units 20 may be direct drive or pulley-driven units. In the shown embodiments, the axial fan units 20 and 20′ have their respective fan axes generally parallel to one another (i.e., parallel, quasi-parallel, within 10 degrees of bring parallel).

Referring to FIGS. 2A, 2B and 3, grills 24 cover the various outlets 23. As show in FIGS. 2A and 2B, a single grill 24 may be sized to cover both axial fans 21, but it is considered to provide one grill 24 per axial fan 21 or per outlet 23. According to an embodiment, the grill 24 is double louvered (also known as double louver grill or grille), with fixed vertical and horizontal louvers, to form a grid of square vents. The double louvered grill is arranged so as to direct the air flow in a direction substantially parallel to the rotational axis of the fans 21. Stated differently, the grill 24 forms a plurality of small air channels each having a direction generally parallel to a rotational axis of the axial fan 21. Other arrangements are considered, such as a louvered grill, circular grill, etc. In an embodiment, the double louvered grill 24 defines square or rectangular vents having dimensions ranging from 0.375″ to 1.125″ (e.g., 0.5″×0.5″) in length and width, with a depth of at least 0.25″, to create the directional air flow.

As shown below, in the ventilation system 10, the axial fan units 20/20′ are oriented and configured with the grills 24 to direct the air in a given cycle. More specifically, the axial fan units 20′ are mounted to a top of refrigerated enclosures A, such that the axial fans 21 are aligned with the plenum E2. Therefore, air from the plenums E1 and E2 is drawn by the axial fan units 20′, in such a way that a vacuum or like pressure differential is created at an end of the plenum E1 facing the alley B. Cold air of the alley B consequently flows into the plenum E1, as a result of the action of the axial fan units 20′.

The ventilation system 10 also features the axial fan units 20 mounted above the alley B in the air space C, and oriented to blow air downwardly. The axial fan units 20 may be suspended from the ceiling D, by any appropriate attachment, such as rods, chains, etc. The axial fan units 20 are spaced apart from the ceiling D, to form a gap F. The gap F may for instance have a height ranging from 6 inches to 24 inches, though it may be more or less.

Therefore, the cold air blown upwardly by the axial fan units 20′ is redirected toward the alley B by the axial fan units 20. However, the air drawn by the axial fan units 20 to the gap F includes ambient air of the air space C, which air is warmer than the air in the alley B. Therefore, the air blown downwardly is a mixture of cold air from the refrigerated enclosures A and warm air of the air space C, resulting in an increase in the temperature average of the air in alley B.

According to an embodiment, a normal to the plane of the front face 22A of the axial fan units 20′ is aligned with the gap F. Stated differently, the normal crosses the gap F. Such an embodiment ensures that a fair amount of cold air is drawn by the axial fan units 20. In an embodiment, the angle θ is determined as a function of the ceiling height to achieve a generally direct air path from the axial fan units 20′ to the gap F. An installer may also orient the axial fan units 20′ to achieve such a generally direct air path.

Referring to FIG. 4, another arrangement of the ventilation system 10 is shown, featuring another set of axial fan units, shown as 20″. The axial fan units 20″ are similar to the axial fan units 20, but are arranged to have the rotational axes generally horizontal. The axial fan units 20 may be aligned with the axial fan units 20′ to be exposed to the colder air blown by the axial fan units 20′. According to an embodiment, a normal to the plane of the front face 22A of the axial fan units 20′ is aligned with the rear face 22B of the axial fan units 20″. Stated differently, the normal crosses rear face 22B of the axial fan units 20″. Such an embodiment ensures that a fair amount of cold air is drawn by the axial fan units 20″. Still in FIG. 4, the ventilation system 10 also features the axial fan units 20 mounted above another alley B1 in the air space C, and oriented to blow air downwardly. Again, the axial fan units 20 may be suspended from the ceiling D, by any appropriate attachment, such as rods, chains, etc. The axial fan units 20 are spaced apart from the ceiling D, to form the gap F. Therefore, the cold air blown upwardly by the axial fan units 20′ is redirected toward the axial fan units 20 by the axial fan units 20″. Therefore, the air may be blown downwardly into alley B1 or other floor space, which air is a mixture of cold air from the refrigerated enclosures A and warm air of the air space C. As alley B (or other floor space) may be without refrigerated enclosures as in FIG. 4, there results some air conditioning in the other alley B. There may be a plurality of axial fan units 20 distributed throughout the facility to provide air conditioning where appropriate or required. Therefore, the ventilation system 10 serves to use the ambient cold near the refrigerated enclosures A to air condition the facilitate.

Referring to FIG. 5, a refrigeration system in accordance with an embodiment of the present disclosure is shown at 50 in relation to the ventilation system 10. The refrigeration system 50 operates a refrigeration cycle devised to provide cold refrigerant to the refrigerated enclosures A. The refrigeration system 50 may operate with any appropriate type of refrigerant, including synthetic refrigerants, CO₂, ammonia, etc. In FIG. 5, there is shown a simplified schematic version of the refrigeration system 50, which refrigeration system 50 may have appropriate hardware and controls, such as receivers, tanks, valves, sensors, etc. The refrigeration system 50 may also have a defrost circuit.

The refrigeration system 50 may have one or more of a compression stage 51, a condensation/heat reclaim stage 52 (shown as having a condensing stage 52A and a reclaim stage 52B, concurrently 52), an expansion stage 53, and an evaporation stage 54, feeding the refrigerated enclosures A, to then cycle back to the compression stage 51. For example, the refrigeration system 50 may be without an expansion stage. In the refrigeration cycle, the compression stage 51 performs a compression of a refrigerant to a high-pressure gas state. The compression stage 51 is in fluid communication with the condensation/heat reclaim stage 52.

The condensation/heat reclaim stage 52 releases heat from the high-pressure gas refrigerant received from the compression stage 51. In the condensing stage 52A, the heat is released to the atmosphere, for instance using roof-top condensers. Alternatively, heat may be recuperated using heat reclaim systems of a heat reclaim stage 52B in series or in parallel with condensers. According to an embodiment, as described below, the heat reclaim stage 52B provides heat to a HVAC system 70. The condensation/heat reclaim stage 52 may have refrigerant tanks to accumulate refrigerant having released heat and ready to be fed to the evaporation stage 54.

The condensed refrigerant is directed to the evaporation stage 54. The evaporation stage 54 typically has numerous evaporators in the refrigeration enclosures A, as well as the necessary expansion valves in the expansion stage 53 if required to set the refrigerant to a suitable condition to absorb heat. In some instances, the evaporators of the evaporation stage 54 may be flooded with liquid refrigerant such that expansion valves are optional.

FIG. 5 also depicts the relation between the refrigerated enclosures A and the ventilation system 10, as described above. A refrigeration controller 60 may be provided to operate concurrently the ventilation system 10, the refrigeration system 50 and/or the HVAC system 70. The refrigeration controller 60 is of the type having one or more processing units, and a non-transitory computer-readable memory communicatively coupled to the processing unit and comprising computer-readable program instructions executable by the processing unit for performing control functions as described herein. For simplicity, the refrigeration controller 60 is shown as being generically connected to the compression stage 51. However, the refrigeration controller 60 may be connected to numerous components of the systems 10, 50, and 70, so as to operate the various cycles of the systems 10, 50 and 70, depending on factors including outdoor temperature and relative humidity, cold demand, heat demand, refrigeration requirements. The refrigeration controller 60 therefore has a plurality of sensors, and is configured to power compressors, condensing units, coils, valves (electronic valves, solenoid valves), etc.

In FIGS. 1 to 4, there has been described the ventilation system 10, which is operated in the manner described above in situations of warmer outdoor temperature (e.g., temperature greater than 20 C). The ventilation system 10 is actuated, for example manually or by the refrigeration controller 60, to recuperate cold heat as released in the environment surrounding the refrigeration enclosures A, to a remainder of the facility, or at least to areas requiring air conditioning (i.e., cooler air). In accordance with an embodiment, the cold heat recuperated by the operation of the ventilation system 10 provides sufficient cold to meet the air-conditioning demand of the facility. Therefore, when the refrigeration controller 60 operates the ventilation system 10, the refrigeration controller 60 may turn off, or may select not to operate a refrigeration cycle of the HVAC system 70. Stated differently, the refrigeration controller 60 may operate the ventilation system 10 to spread the cold heat recuperated from the refrigerated enclosures A, as preferred over generating cold in the HVAC system 70.

The available cold heat may exceed the air-conditioning demand, to the extent that HVAC 70 may be required to provide heat to its ventilated air. As shown in FIG. 5, the heat reclaim stage 52B of the refrigeration system 50 is connected to the HVAC system 70, for the HVAC system 70 to reclaim heat from the refrigeration system 50. In an embodiment, one or more coils of the refrigerant of the refrigerant system 50 extend into a duct of the HVAC system 70, for the air circulating in the HVAC system 70 to be warmed up by recuperating heat from the refrigeration system 50, for example as part of dehumidification, or for heating. In another embodiment, a coolant (e.g., a secondary refrigerant) such as brine, glycol, water, circulates in a circuit between the refrigeration system 50 and the HVAC system 70. The circuit has coils in both the refrigeration system 50 and the HVAC system 70, with additional components, such as a pump.

Consequently, the refrigeration controller 60 may be triggered to provide heat when the floor temperature is below a given threshold. The refrigeration controller 60 may actuate appropriate valves for the refrigeration system 50 to direct its refrigerant to the heat reclaim stage 52B. In parallel, the refrigeration controller 60 may actuate the fans of the HVAC system 70 for air to be convected through the HVAC system 70, and in the process be warmed up by the heat reclaim relation with the heat reclaim stage 52B. The warm air may then be supplied to the facility via the ventilation ducts of the HVAC system 70. The refrigeration controller 60 directs such operation, while in parallel the ventilation system 10 operates to meet the air-conditioning demand of the facility.

An advantage of using the heat reclaim stage 52B resides in the reduced load on the condensing stage 52A. As heat is reclaimed by the HVAC system 70, the condensing units of the condensing stage 52A have a lesser amount of heat to release. It has been known that a liquid may be used to assist the heat release of the condensing stage 52 (e.g., water sprayed on the coils of the condensing units). The use of a cooling liquid may not be required when the HVAC system 70 reclaims the heat, whereby the refrigeration controller 60 may block the operation of water sprays. There results a dehumidification of the facility.

In all, the refrigeration controller 60 operates the systems 10, 50 and 70, in such a way that the air-conditioning/refrigeration cycle of the HVAC system 70 may need not be operated, or may only be minimally operated, in spite of an outdoor temperature above 20 C, or above 25 C, or above 30 C, depending on the floor size.

Now referring to FIGS. 6 and 7, yet another HVAC system 80 will now be described. The HVAC system 80 may be the one shown as HVAC system 70 in FIG. 5, or the HVAC system 70 may be a component of the HVAC system 80 of FIGS. 6 and 7. In this embodiment, the HVAC system 80 includes a central unit 82 that in this embodiment is mounted onto a roof (RF) of a building (BLDG) and serves one or more spaces (SP1, SP2, . . . SPn) in the building (BLDG). Examples of the spaces (SP1, SP2, . . . SPn) include occupied spaces (i.e. spaces normally occupied by people) and non-occupied spaces (i.e. mechanical rooms for example). The spaces may or may not be closed off or delimited by walls. For example, some of the shown spaces concurrently define an open space, such as the shopping area of a supermarket, as an example. The central unit 82 serves the space(s) (SP1, SP2, . . . SPn) by selectively bringing heat to and/or carrying heat away from the spaces (SP1, SP2, . . . SPn) solely via refrigerant lines (R) extending from the central unit 82, as explained below. The refrigerant lines (R) that may be associated with the HVAC system 80 are shown schematically in FIGS. 6 and 7.

Only some of the refrigerant lines (R) are labeled in FIG. 6, and multiple refrigerant lines (R) of FIG. 6 are schematically shown with double-ended arrows (R) in FIG. 7, to maintain clarity of the figure, though in reality the lines (R) may form loops. In an aspect, using solely refrigerant lines (R) for transporting heat between the central unit 82 and the spaces (SP1, SP2, SPn) may help reduce the amount of ductwork that may be required to suitably air condition the building (BLDG), which may provide different advantages depending on each particular building (BLDG) and its use for example. As an example, the advantages may include saved space, easier installation, improved aesthetics, and the like. A non-limiting embodiment of the central unit 82 and a particular non-limiting embodiment of a refrigerant line (R) arrangement that may be used are described next, in detail.

Referring to FIG. 6, in this embodiment, the central unit 82 includes a compressor 84 operable to provide compressed refrigerant, such as compressed carbon dioxide (CO₂) for example, though other refrigerants may be used as well. The central unit 82 further includes a condenser 86 at a refrigerant inlet 86A thereof fluidly connected to a refrigerant outlet 84B of the compressor 84 via a compressed refrigerant line (R) to receive the compressed refrigerant from the compressor 84, cooling the refrigerant down as it passes through the condenser 86. The condenser 86 further includes a refrigerant outlet 86B via which the refrigerant may be supplied to one or more different terminal units 88 disposed in one or more of the spaces (SP1, SP2, SPn) in the building (BLDG). The condenser 86 may take various forms, and may for example include a gas cooler, a cooling tower, heat reclaim units, etc.

Only two of the terminal units 88, a horizontal terminal unit 88, and a vertical terminal unit 88′, are shown in FIG. 6, to maintain clarity. The horizontal terminal unit 88 may be similar to the vertical terminal unit 88′ with respect to components and may differ only with respect to airflow direction, as described later herein. The rest of the terminal units 88 may be similar, and are therefore not described in detail. Therefore, the components and refrigerant connections of only one of the terminal units 88 are described in detail herein. Terminal units 88 may be distributed at various locations in the facility.

The supply of refrigerant from the refrigerant outlet 86B of the condenser 86 may be used to enable the one or more terminal units 88 to cool one or more of the spaces (SP1, SP2, . . . SPn) in the building (BLDG). In turn, for cooling the refrigerant passing through the condenser 86 to make the supply of refrigerant from the refrigerant outlet 86B available, the central unit 82 further includes a fan 90. The fan 90 is operatively connected to the condenser 86 to move air through the condenser 86 and thereby carry away heat from the refrigerant passing through the condenser 86. The fan 90 may be any suitable fan and/or may be multiple fans 96. The central unit 82 may have other elements that may be selected to enable operation of the central unit 82 as described herein in each particular embodiment and application thereof. Such additional elements, such as one or more air filters, refrigerant filters, controller(s), valve(s), sensor(s), and the like, may be conventional and are therefore not described in detail herein.

As an example, the central unit 82 may include and/or may be connected to one or more controllers 91, such as conventional controller(s) for example, selected to provide the functionality described herein. In some embodiments, the controller(s) 91 may be the controller 60 described above. As shown, the one or more controllers 91 may be operatively connected to the respective components of the HVAC system 80, including the compressor 84, the fan 90, control valves, sensors and the like, to operate the central unit 82 and the rest of the HVAC system 80 according to a suitable control sequence. The respective electronic connections and control sequences may be conventional and are therefore not described herein in detail.

The present embodiment of the refrigerant line (R) arrangement and two of the terminal units 88 shown in FIG. 6 are now described in further detail. As shown in FIG. 6, refrigerant from the refrigerant outlet 86B of the condenser 86 may pass through one or more refrigerant expansion valves 92 for further reducing the pressure of the refrigerant before introducing it into the terminal unit(s) 88. The one or more refrigerant expansion valves 92 may be for example disposed fluidly between the refrigerant outlet 86B of the condenser 86 and refrigerant inlets 93A of cooling coils 93 of the terminal units 88. The one or more refrigerant expansion valves 92 and any associated sensor(s) and controls may be conventional refrigerant expansion valve(s) and sensors/controls.

Still referring to FIG. 6, the terminal unit 88 in this embodiment includes, in serial air flow communication, the cooling 93 and a heating coil 94 downstream of the cooling 93 relative to airflow through the terminal unit 88. Further as shown in FIG. 6, in this embodiment each of the terminal units 88 includes at least one fan 96 operable to move air through the cooling 93 and the heating coil 94. As shown, in this embodiment, the at least one fan 96 is a plurality of axial fans 96 disposed fluidly in parallel relative to each other. While this fan arrangement provides airflow advantages in the present embodiment, in other embodiments, one or more of the terminal units 88 may have other fan arrangements. The axial fans 96 may have a similar configuration as in FIGS. 2A and 2B, with grills to assist in directing the air in a given direction.

As shown in FIG. 6, the cooling 93 is fluidly connected (via respective refrigerant lines (R)): i) at a refrigerant inlet 93A thereof, to the refrigerant outlet 86B of the condenser 86 to receive refrigerant from the condenser 86, and ii) at a refrigerant outlet 93B thereof, to a refrigerant inlet 86A of the compressor 86 to supply evaporated refrigerant to the refrigerant inlet 86A of the compressor 86. Further as shown in FIG. 6, in this embodiment the heating coil 94 is fluidly connected (via respective refrigerant lines (R)): i) at a refrigerant inlet 94A thereof, to the compressed refrigerant line (R) connecting the refrigerant inlet 86A of the condenser 86 to the refrigerant outlet 84B of the compressor 84, at a first location (L1) that is fluidly between the refrigerant outlet 84B of the compressor 84 and the refrigerant inlet 86A of the condenser 86, and ii) at a refrigerant outlet 94B thereof, to said compressed refrigerant line (R) at a second location (L2) that is fluidly between the first location (L1) and the refrigerant inlet 86A of the condenser 86. Hence, the heating coils 94 may be heat reclaim units, as they may recuperate heat from the compression of the refrigerant. In an embodiment, the refrigerant is CO₂, and the compressor(s) 84 is drive to compressor the refrigerant transcritically to generate enough for the hearting coils 94 and other facility heat demands. The heat demands may include hot water, food heaters, etc. The transcritical operation of the compressor(s) 84 may even occur in warmer months, including summer, to warm up the cool air from refrigerated enclosures, in the dehumidification process, etc.

In this embodiment, to help prevent backflow of the refrigerant from the second location (L2) toward the first location (L1), the HVAC system 80 further includes a check valve 98 in the compressed refrigerant line (R) fluidly connecting the first and second locations (L1), (L2). The check valve 98 is oriented to allow refrigerant flow from the first location (L1) toward the second location (L2) and to prevent refrigerant flow from the second location (L2) toward the first location (L1). In other embodiments, a different flow arrangement may be used. The check valve 98 is one of numerous valves that may be present, and that include pressure-regulating valves, e.g., for transcritical operation (which may be at 92), manual, valves, etc.

In this embodiment, refrigerant flow to respective ones of the cooling 93 and the heating coil 94 are controlled via respective dedicated refrigerant flow control valves 98, 100. As shown, in this embodiment, the refrigerant flow control valve 98 controlling refrigerant flow through the cooling 93 is fluidly upstream of the refrigerant inlet 93A of the cooling 93. Similarly, the refrigerant flow control valve 100 controlling refrigerant flow through the heating coil 94 is fluidly upstream of the refrigerant inlet 94A of the heating coil 94. The valves 98, 100 in this embodiment are operatively connected to the controller 91 to be operable by the controller 91 according to a control sequence that may be selected to be suit each particular embodiment and application of the HVAC system 80.

As shown in FIG. 6, in this embodiment, the terminal unit 88 that is serving occupied space (SP1) is a horizontal terminal unit 88 installed in a top portion (TP) space (SP1). In this embodiment, the building (BLDG) is a supermarket and the space (SP1) is an occupied space and more particularly an isle in the supermarket. The horizontal terminal unit 88 is configured such that the fan(s) 96 of the horizontal terminal unit 88 eject(s) air out of the horizontal terminal unit 88 in a horizontal direction (HD) when the horizontal terminal unit 88 is installed and operating. More particularly, in this embodiment the fan(s) 96 of the horizontal terminal unit 88 are a plurality of axial fans 96, which provides some advantages in at least some applications. However, in other embodiments, one or more of the horizontal terminal unit(s) 88 may have other type(s), number(s), and/or arrangements of fan(s) 96.

Also as shown in FIG. 6, in this embodiment, the terminal unit 88 that is serving occupied space (SP4) is a vertical terminal unit 88′ in a top portion (TP) space (SP4). The vertical terminal unit 88′ is configured such that the fan(s) 96 of this vertical terminal unit 88′ eject(s) air out of the vertical terminal unit 88′ in a vertical direction (VD) when the vertical terminal unit 88′ is installed and operating, in a downward direction. Space (SP4) in this embodiment is another isle in the supermarket. In this embodiment, the fan(s) 96 of the vertical terminal unit 88′ may be a single axial fan, or multiple axial fans, oriented to have the rotational axis vertical, which provides some advantages in at least some applications. However, in other embodiments, one or more of the vertical terminal unit(s) 88′ may have other type(s), number(s), and/or arrangements of fan(s) 96.

In operation, the controller(s) 91 of the HVAC system 80 may monitor one or more control sequences and variables in one or more of the spaces (SP1, SP2, SPn), such as temperatures, relative humidity, and occupancy for example, with the particular set of variables being selected to suit each particular embodiment and application of the HVAC system 80. As an example, as mentioned above, in the embodiment shown in FIG. 6, the application of the HVAC system 80 is a supermarket. In this example, the occupied space (an aisle) (SP1) above which the horizontal terminal unit 88 is installed fluidly connects to an adjacent occupied space (a corridor, for example) (SP2) of the supermarket building (BLDG) via their respective top portions (TP), only one of which is labeled to maintain clarity.

In this embodiment of the building (BLDG), the horizontal terminal unit 88 is installed to move air from the top portion (TP) of the occupied space (SP1) toward the top portion (TP) of the occupied space (SP2). The occupied space (SP1) includes a refrigerated enclosure (A), such as a food refrigerator, disposed proximate a wall (W) of the occupied space (SP1) at a rear (AR) of the refrigerated enclosure (A) and proximate a floor (FL) of the occupied space (SP1) at a bottom (AB) of the refrigerated enclosure (A). Further, an axial fan unit 20′, as described above with respect to other embodiments, is disposed proximate a top (AT) of the refrigerated enclosure (A). The axial fan unit 20′ is oriented relative to the space (SP1) to direct air from a space/plenum (E2) defined between: the rear (AR) of the refrigerated enclosure (A) and the part of the wall (W) facing the rear (AR) of the refrigerated enclosure (A). As shown with airflow arrows (unlabeled) in FIG. 6, the space/plenum (E2), the axial fan unit 20′ directs air upward toward an air intake 88A of the horizontal terminal unit 88.

Still referring to FIG. 6, further in this embodiment, the horizontal terminal unit 88 is oriented relative to the space (SP1) to direct air along the top portion (TP), and more particularly in this embodiment along a ceiling (CLG) defining the occupied spaces (SP1), (SP2), toward an axial fan unit 20 as that unit 20 is described above. The axial fan unit 20 is installed in the top portion (TP) of the occupied space (SP2) and is oriented relative to the space (SP2) to direct air from the top portion (TP) of the occupied space (SP2) downward toward a bottom portion (BP) of the occupied space (SP2). Accordingly, at least when the refrigerated enclosure (A), the horizontal terminal unit 88, and the axial fan unit 20 operate simultaneously, the cold air from the refrigerated enclosure (A) may first move down to the floor (FL).

The air may then be entrained, by negative pressure generated by the axial fan unit 20′ in the space/plenum E2, first into the space/plenum E1 below the bottom (AB) of the refrigerated enclosure (A), then into the space/plenum E2, and may then propel the air to the inlet 88A of the horizontal terminal unit 88. The horizontal terminal unit 88 may then move the air to an air inlet 20A of the axial fan unit 20′. Finally, the axial fan unit 20′ may move the air down into the bottom portion (BP) of the occupied space (SP2). These airflows are shown with unlabeled airflow arrows in FIG. 6. The axial fan units 20, 20′ may in some embodiments each have plurality of axial fans disposed fluidly in parallel relative to each other, as shown for example in FIGS. 2B and 3.

In some embodiments, the bottom portion (BP) of the occupied space (SP2) may be the portion of the occupied space (SP2) that is occupied by visitors to the building (BLDG). In some embodiments, this arrangement of units and resulting airflows may help reduce or eliminate overcooling of the bottom portion (BP) of the space (SP1), which may be the portion that is occupied by visitors to the building (BLDG). In some embodiments, this may allow to reduce or eliminate heating that may otherwise be required to counteract overcooling of the bottom portion (BP) of the space (SP1). Accordingly, in some embodiments, the arrangement of units and resulting airflows described above may help reduce energy consumption of the building (BLDG).

To help further improve efficiency of the HVAC system 80, in this embodiment the horizontal terminal unit 88 is spaced from the ceiling (CLG) to define an air plenum (PL) between the horizontal terminal unit 88 and the ceiling (CLG). Similarly, the axial fan unit 20′ is spaced from the ceiling (CLG) to define an air plenum (PL) between its air inlet 20A and the ceiling (CLG). In some operating conditions of the building (BLDG), hot air from one or more of the spaces (SP1), (SP2) (SPn) may rise and collect in these plenums (PL), and may be mixed with the cooler air coming from one or more axial units 20′ that may be disposed at the top-rear of one or more refrigerated enclosures (A) in one or more of the spaces (SP1), (SP2) (SPn), as described above with regard to the refrigerated enclosure (A) in space (SP1).

In some cases and operating conditions, such mixing of warmer air with colder air in the plenums (PL) and subsequent delivery to one or more occupied portions of the one or more of the spaces (SP1), (SP2) (SPn) may help improve occupant comfort in the one or more of the spaces (SP1), (SP2) (SPn). This mixing may also help reduce energy consumption of the HVAC system 80 by “passively” reheating the cold(er) air entering the plenums (PL) with the warm or hot air in the plenums (PL). Here, the term “passively” is used to mean “without having to generate additional heat via a source such as electricity or combustion of a fuel”.

For cases where the passive reheat may be insufficient, the controller(s) 91 may be programmed to open the control valve(s) 100 associated with the heating coils 94 of the corresponding one or more of the terminal units 88 and may thereby actively reheat air before it is supplied to the occupied portions of the spaces (SP1), (SP2) (SPn). To this end, and as shown in FIG. 6 with regard to space (SP4) for example, a given space may have vertical terminal unit 88′ may be used which may have both a cooling coil 93 and a reheat/heating coil 94, as described above. In such cases, air in the plenum (PL) defined by the vertical terminal unit 88′ may be cooled and/or heated and/or reheated actively by the cooling coil(s) 93 and the reheat/heating coil(s) 94 of the vertical terminal unit 88′, and may be subsequently supplied in the downward direction (VD) to the occupied portion of the space (SP4) by the fan(s) 96 of the vertical terminal unit 88′. This airflow is shown in FIG. 6.

Yet further as shown in FIG. 6, in this embodiment, the HVAC system 80 further includes a water unit 102 operatively connected to the central unit 82 by respective refrigerant lines (R). In this particular embodiment, the water unit 102 is a conventional domestic hot water tank (DHWT) with a volume (V) for storing water from a conventional domestic water supply (DWS) of the building (BLDG), and a heat exchanger 104 disposed in the volume (V). In this embodiment, the heat exchanger 104 is a conventional refrigerant-to-water heat exchanger at a refrigerant inlet 104A thereof fluidly connected to a suitable refrigerant supply line (R) from the compressor 84.

More particularly, the refrigerant inlet 104A is fluidly connected to a compressed refrigerant line (R) at the first location (L1) described above. In this embodiment, at a refrigerant outlet 104B thereof, the heat exchanger 104 is fluidly connected to a compressed refrigerant line (R) at the second location (L2) described above. Although not shown herein, similar to the heating coils 94, refrigerant flow through the heat exchanger 104 may be controlled via one or more suitable control valves that may be fluidly upstream or downstream of the heat exchanger 104, relative to refrigerant flow therethrough. In use, refrigerant from the outlet 84B of the compressor 84 may be directed through the heat exchanger 104 and may heat water in the domestic hot water tank 102, making it available for various uses in the building (BLDG) via a conventional domestic hot water supply (DHWS).

In at least some applications and operating conditions such as for example times when the building (BLDG) experiences predominantly or solely cooling loads, using heat removed from the spaces (SP1), (SP2) . . . (SPn) in a water unit such as the domestic hot water tank 102 may help cool refrigerant before it reaches the inlet 86 of the condenser 86. This may help reduce an energy consumption of the HVAC system 80.

The above description is meant to be exemplary only. The components and parts described herein above may be constructed from existing components and parts to provide for the particular arrangements of systems and functionality described herein above. One skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the technology disclosed herein. Certain aspects of the above systems, such as temperature and/or humidity and/or occupancy sensors one or more of which may be used in some embodiments for example, have not been shown and/or described in detail herein. Where this is the case, the aspects may be implemented using conventional technology. 

1. A ventilation system comprising: a plurality of axial fan units, each having at least one axial fan having a rotational axis generally parallel to a downstream flow caused by the axial fan, and at least one grill positioned adjacent to the at least one axial fan in a downstream flow path of the axial fan unit, the at least one grill directing an air flow of the axial fan; wherein at least a first series of the plurality of axial fan units is adapted to be positioned at a top of a plenum arrangement extending from a bottom front of a refrigerated enclosure, to a rear back of the refrigerated enclosure, said top being at a top of the rear back; wherein at least a second series of the plurality of axial fan units is adapted to be positioned above an area to cool and oriented to project its downstream flow in a downward direction to direct its downstream flow to said area to cool; and wherein the first series of the plurality of axial fan units is oriented to project its downstream flow in an upward direction toward the second series of the plurality of axial fan units such that the first series is adapted to direct air from the plenum arrangement to the second series.
 2. The ventilation system according to claim 1, wherein the at least one grill is at least one double louver grill.
 3. The ventilation system according to claim 2, wherein a plurality of vents defined by the double louver grill each have a rectangular shape having a length ranging between 0.375″ and 1.125″.
 4. The ventilation system according to claim 3, wherein the plurality of vents defined by the double louver grill each have a width ranging between 0.375″ and 1.125″.
 5. The ventilation system according to claim 3, wherein the plurality of vents defined by the double louver grill each have a depth of at least 0.25″.
 6. The ventilation system according to claim 1, comprising one of the at least one grill for each said axial fan unit.
 7. A refrigeration controller system for operating a refrigeration, a ventilation system and a HVAC system comprising: a processing unit, and a non-transitory computer-readable memory communicatively coupled to the processing unit and comprising computer-readable program instructions executable by the processing unit for operating the refrigeration system to cool refrigerated enclosures; operating the ventilation system according to claim 1 to provide cold heat to a facility recuperated from said refrigerated enclosures; reclaiming heat from the refrigeration system; and operating the HVAC system with the heat reclaimed from the refrigeration system to provide heated air; wherein the refrigeration controller system operates when an outdoor temperature is greater than 20 C.
 8. A heating, ventilating and air conditioning (HVAC) system, comprising: a central unit, comprising: a compressor operable to provide compressed refrigerant, a condenser at a refrigerant inlet fluidly connected to a refrigerant outlet of the compressor via a compressed refrigerant line to receive the compressed refrigerant from the compressor, and a first fan operatively connected to the condenser to move air through the condenser; a plurality of terminal units, each terminal unit of the plurality of terminal units comprising, in serial air flow communication: a cooling coil fluidly connected: at a refrigerant inlet thereof, to a refrigerant outlet of the condenser to receive refrigerant from the condenser, and at a refrigerant outlet thereof, to a refrigerant inlet of the compressor to supply evaporated refrigerant to the refrigerant inlet of the compressor; a heating coil fluidly connected: at a refrigerant inlet thereof, to the compressed refrigerant line at a first location that is fluidly between the refrigerant outlet of the compressor and the refrigerant inlet of the condenser, and at a refrigerant outlet thereof, to the compressed refrigerant line at a second location that is fluidly between the first location and the refrigerant inlet of the condenser; and a second fan operable to move air through the cooling coil and the heating coil.
 9. The HVAC system of claim 8, wherein the plurality of terminal units includes a horizontal terminal unit configured such that the second fan of the horizontal terminal unit ejects air out of the horizontal terminal unit in a horizontal direction when the horizontal terminal unit is installed.
 10. The HVAC system of claim 9, wherein the second fan of the horizontal terminal unit is a plurality of axial fans.
 11. The HVAC system of claim 8, wherein the plurality of terminal units includes a vertical terminal unit configured to supply air in a vertical direction when the vertical terminal unit is installed.
 12. The HVAC system of claim 11, wherein the second fan of the vertical terminal unit is a single axial fan.
 13. The HVAC system of claim 8, further comprising a check valve in the compressed refrigerant line fluidly between the first and second locations, the check valve oriented to allow refrigerant flow from the first location toward the second location and to prevent refrigerant flow from the second location toward the first location.
 14. The HVAC system of claim 8, further comprising a water unit a volume for storing water and a heat exchanger disposed in the volume, the heat exchanger fluidly connected: at a refrigerant inlet thereof, to the compressed refrigerant line at the first location, and at a refrigerant outlet thereof, to the compressed refrigerant line at the second location.
 15. The HVAC system of claim 14, wherein the water unit is a domestic hot water tank.
 16. The HVAC system of claim 8, further comprising a refrigerant expansion valve fluidly between the refrigerant outlet of the condenser and the refrigerant inlets of the cooling coils of the plurality of terminal units.
 17. The HVAC system of claim 8, further comprising a refrigerant flow control valve fluidly upstream of the refrigerant inlet of the heating coil of each of the plurality of terminal units.
 18. The HVAC system of claim 8, wherein the refrigerant flow control valve is a first refrigerant flow control valve and further comprising a second refrigerant flow control valve fluidly upstream of the refrigerant inlet of the cooling coil of each of the plurality of terminal units. 